Driving support apparatus for a vehicle

ABSTRACT

A driving support apparatus for a vehicle is provided. The apparatus causes an alarm unit to issue an alarm based on a lane marking of an own lane in which an own vehicle runs. The apparatus includes a leading vehicle detection section that determines a leading vehicle running in the own lane, a crossing over determination section that determines whether or not the leading vehicle has crossed over the lane marking present at an opposite side of the target, when a target is present at a left side or a right side of the leading vehicle in the own lane, and an alarm inhibition section that inhibits the alarm based on a result of the determination whether or not the leading vehicle has crossed over the lane marking present at the opposite side of the target.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority fromearlier Japanese Patent Application No. 2015-219820 filed Nov. 9, 2015,the description of which is incorporated herein by reference.

BACKGROUND

(Technical Field)

The present invention relates to a driving support apparatus for avehicle.

(Related Art)

Conventionally, various driving support techniques have been proposedwhich are for supporting driving of the driver of a vehicle. Forexample, a technique is known in which when an own vehicle has deviatedfrom a driving lane, an alarm is issued to the driver of the own vehicle(e.g. refer to JP-A-2008-117054).

However, in the above conventional technique, it can be considered thatdeviation of the own vehicle from the traveling lane is allowed in somesurrounding environments in which, for example, there are stopped orparked vehicles, persons, structures, or the like at the edge of thelane in which the own vehicle runs. In this case, it can be consideredthat an alarm indicating that the own vehicle has deviated from thetraveling lane may be unnecessarily issued though the driver ispurposefully making the own vehicle deviate from the driving lane. Inthis regard, if an unnecessary alarm is issued, the driver may feeldiscomfort. Hence, There is room for improvement.

SUMMARY

An embodiment provides a driving support apparatus for a vehicle, theapparatus being able to appropriately cause an alarm to be issued whichindicates that an own vehicle has crossed over a lane marking.

As an aspect of the embodiment, a driving support apparatus for avehicle is provided. The apparatus causes an alarm unit to issue analarm based on a lane marking of an own lane in which an own vehicleruns. The apparatus includes: a leading vehicle detection section thatdetermines a leading vehicle running in the own lane; a crossing overdetermination section that determines whether or not the leading vehiclehas crossed over the lane marking present at an opposite side of thetarget, when a target is present at a left side or a right side of theleading vehicle in the own lane; and an alarm inhibition section thatinhibits the alarm based on a result of the determination whether or notthe leading vehicle has crossed over the lane marking present at theopposite side of the target.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a drawing showing a configuration of a driving support system;

FIG. 2 is a drawing showing a situation in which a vehicle is allowed tocross over a lane marking;

FIG. 3 is a drawing illustrating a lateral distance H1 and allowancedetermination;

FIG. 4 is a flowchart illustrating a processing procedure for inhibitingan alarm;

FIG. 5 is a drawing illustrating a lateral distance H2 and allowancedetermination; and

FIG. 6 is a flowchart illustrating a processing procedure for inhibitingan alarm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Hereinafter, an embodiment of a driving support apparatus for a vehiclewill be descried with reference to the drawings. The driving supportapparatus according to the present embodiment is mounted in the vehicle,and performs various driving support processes when the driver drivesthe vehicle. First, the schematic configuration of the driving supportsystem will be described with reference to FIG. 1.

In FIG. 1, a driving support ECU 10, which is a driving supportapparatus, is connected with an imaging unit 21, a radar 22, a yaw ratesensor 23, a steering angle sensor 24, and a vehicle speed sensor 25,from each of which the driving support ECU 10 receives detection signalsand various kinds of information.

The imaging unit 21 is an in-vehicle camera and includes a CCD camera, aCMOS image sensor, a near-infrared camera, or the like. The imaging unit21 acquires images of surrounding environments of the vehicle includinga driving lane of the vehicle. Then, the imaging unit 21 generates imagedata representing the acquired images and sequentially outputs the imagedata to the driving support ECU 10. The imaging unit 21 is disposed, forexample, in the vicinity of the upper end of the front windshield of thevehicle, and acquires images of an area extending ahead of the vehicleand in a predetermined angular range centering on the imaging axisthereof. Note that the imaging unit 21 may be a monocular camera or astereo camera.

The radar 22 transmits an electromagnetic wave as a transmission waveand receives a reflected wave thereof to detect a target, and isconfigured by a millimeter-wave radar, a laser radar, or the like. Theradar 22 is mounted on the front part of the vehicle, and scans an area,which extends ahead of the vehicle and over a range of a predeterminedangle centering on the optical axis thereof with, a radar signal. Then,the radar 22 generates distance measurement data based on the timeperiod between the transmission of an electromagnetic wave ahead of thevehicle and the reception of a reflected wave, and sequentially outputsthe generated data to the driving support ECU 10. The distancemeasurement data includes information on a direction in which an objectis present, the distance to the object, and a relative speed.

The yaw rate sensor 23 has, for example, an oscillator such as a tuningfork, and detects distortion generated in the oscillator based on theyaw moment of the own vehicle to detect a yaw angle of the own vehicle.The steering angle sensor 24 detects an operation angle of the steeringwheel, that is, a steering angle. The vehicle sensor 25 is provided to arotating shaft transferring power to the wheels of the vehicle, andoutputs a detection signal depending on the vehicle speed.

In addition, the driving support ECU 10 is connected with an alarm unit31. The alarm unit 31 informs the driver of the fact that a dangeroussituation has arisen in the own vehicle, the fact that any prohibitedact has been carried out, or the like. The alarm unit 31 is, forexample, a loudspeaker provided in the vehicle interior. When thedriving support ECU 10 outputs a control command, the alarm unit 31gives information to the driver by a sound or the like. Note that,instead of the alarm of the alarm unit 31, information may be given tothe driver by applying reaction force against vibration and drivingoperation to the driver from the steering wheel. In addition,information may be given to the driver by indication on a display panelsuch as a display provided to an instrument panel.

The driving support ECU 10 is a computer including a CPU, a ROM, a RAM,and an I/O. The driving support ECU 10 executes a program installed inthe ROM to achieve various functions. Specifically, as basic operation,the driving support ECU 10 determines whether or not the own vehicle hascrossed over a lane marking of the lane in which the own vehicle runs(hereinafter, referred to as own lane). If the driving support ECU 10determines that the own vehicle has crossed over a lane marking, thedriving support ECU 10 outputs a control command to the alarm unit 31.Thereby, the alarm unit 31 gives information to the driver.

In addition, in the present embodiment, even when the own vehicle hascrossed over a lane marking of the own lane, issuing an alarm isinhibited if the own vehicle is allowed to cross over the lane marking.As a means for inhibiting an alarm, the driving support ECU 10 achieves,in addition to the above functions, functions of a target detectionsection 11, a leading vehicle detection section 12, a crossing overdetermination section 13, an allowance determination section 14, and analarm inhibition section 15.

Based on information (image data and distance measurement data) on anobject obtained by the imaging unit 21 and the radar 22, the targetdetection section 11 detects a target included in the data. For example,the target detection section 11 combines information on the objectextracted from the image data of the imaging unit 21 with information onthe object extracted from the distance measurement data of the radar 22to detect a target. Instead of this, a target may be detected by usingany one of the information on the object extracted from the image dataof the imaging unit 21 and the information on the object extracted fromthe distance measurement data of the radar 22. The target detected bythe target detection section 11 is output to the leading vehicledetection section 12.

Based on the target detected by the target detection section 11, theleading vehicle detection section 12 detects a forward vehicle, which isone of the vehicles running ahead of the own vehicle and in the ownlane, in which the own vehicle runs, as a leading vehicle on conditionthat the forward vehicle is closest to the own vehicle (the distancebetween the own vehicle and the forward vehicle is shorter than thedistances between the own vehicle and other vehicles running ahead ofthe own vehicle and in the own lane). In addition to the above, aleading vehicle may be detected by using a lateral distance between atravel path of the forward vehicle and the own vehicle or an own laneprobability map. In addition, the leading vehicle detection section 12detects one of the forward vehicles as a leading vehicle on conditionthat the difference between the width of the own vehicle and the widthof the leading vehicle is equal to or less than a threshold value Th1.

The crossing over determination section 13 determines whether or not theleading vehicle has crossed over a lane marking of the own lane.Specifically, the crossing over determination section 13 recognizes awhite line (lane marking) of the own lane based on the imaging result ofthe imaging unit 21. Then, the crossing over determination section 13detects an obstacle at the left side or the right side of the leadingvehicle in the own lane, and determines whether or not the leadingvehicle has crossed over a lane marking present at the opposite side ofthe obstacle. The result of the determination whether or not the leadingvehicle has crossed over a lane marking present at the opposite side ofthe obstacle is output to the alarm inhibition section 15. Note that thelane marking is not limited to a white line but may be a solid line suchas a yellow line, or Botts' Dots. Furthermore, the lane marking may be avirtual lane obtained based on roadside information on guardrails or thelike.

The allowance determination section 14 determines whether or not the ownvehicle is in a situation in which the own vehicle is allowed to crossover a lane marking. Specifically, it is determined whether or not theown vehicle is in a situation in which the own vehicle is allowed to runwhile crossing over a lane marking based on the size of a travel area(available unobstructed travel area) of the own vehicle, the travel areabeing other than an area of the own lane which is occupied by obstacles.The result of the determination whether or not the own vehicle isallowed to cross over a lane marking is output to the alarm inhibitionsection 15.

The alarm inhibition section 15 determines not to cause an alarm to beissued even when the own vehicle has crossed over a lane marking, basedon the result of the determination whether or not the leading vehiclehas crossed over the lane marking present at the opposite side of theobstacle and the result of the determination whether or not the ownvehicle is allowed to cross over the lane marking.

The inhibition about an alarm will be further described. Depending onthe surrounding environments of the own vehicle in which, for example,there are obstacles such as stopped or parked vehicles, persons,structures, and the like at the edge of the own lane, it can beconsidered that the own vehicle may be allowed to cross over a lanemarking.

Referring to FIG. 2, a specific example will be described in which anown vehicle is allowed to cross over a lane marking. In FIG. 2, an ownvehicle M1 and a leading vehicle M2 running ahead of the own vehicle M1are running in a straight line in an own lane L, and vehicles arepresent, which are waiting for right turning, at the right side of theleading vehicle M2. In this case, the vehicles waiting for right turningin the own lane L are present as an obstacle B with respect to theleading vehicle M2 and the own vehicle M1 running in a straight line inthe own lane L. As shown in FIG. 2, when the leading vehicle M2 runs inthe own lane L and in a travel area R at the left side of the obstacleB, if the travel area R is narrower than the width of the leadingvehicle M2, the leading vehicle M2 crosses over a lane marking Dopposite to the obstacle B. In addition, also when the own vehicle M1runs in the travel area R following the leading vehicle M2, the ownvehicle M1 crosses over the lane marking D. At this time, the alarm unit31 issues an alarm indicating that the own vehicle M1 has crossed overthe lane marking D. In this case, although the driver has purposefullymade the own vehicle M1 cross over the lane marking D, an alarmindicating that the own vehicle M1 has crossed over the lane marking Dis unnecessarily issued.

Thus, in the present embodiment, if the crossing over determinationsection 13 determines that the leading vehicle has crossed over the lanemarking opposite to the obstacle, and if the allowance determinationsection 14 determines that the width of the leading vehicle is smallerthan that of the travel area, the alarm inhibition section 15 determinesnot to cause an alarm to be issued even if the own vehicle crosses overthe lane marking.

The determination whether or not the own vehicle is allowed to crossover a lane marking will be described with reference to FIG. 3. In FIG.3, the own vehicle M1 and the leading vehicle M2 running ahead of theown vehicle M1 are running in the own lane L, and the obstacle B ispresent right next to the leading vehicle M2. In addition, the lanemarking D is present at the left side of the leading vehicle M2. Theallowance determination section 14 obtains a lateral distance H1, whichis a distance between the lateral position of the lane marking D in thelane width direction and the lateral position of the obstacle B, and thewidth W of the leading vehicle M2, and determines whether or not thewidth W of the leading vehicle M2 is larger than the lateral distanceH1. Note that the lateral distance H1 and the width W are obtained fromthe imaging result of the imaging unit 2. If the width W of the leadingvehicle M2 is larger than the lateral distance H1, when the leadingvehicle M2 runs in the travel area R, the leading vehicle M2 crossesover the lane marking D. In this case, when the own vehicle M1 runs inthe travel area R following the leading vehicle M2, it can be consideredthat the driver of the own vehicle M1 purposefully makes the own vehicleM1 cross over the lane marking D. Hence, when the leading vehicle M2 hascrossed over the lane marking D, if it is determined that the width W ofthe leading vehicle M2 is larger than the lateral distance H1, it isdetermined that an alarm is not caused to be issued even if the ownvehicle M1 crosses over the lane marking D.

Next, a processing procedure for inhibiting an alarm performed by thedriving support ECU 10 will be described with reference to the flowchartin FIG. 4. The present process is repeatedly performed by the drivingsupport ECU 10 at predetermined intervals while the vehicle is running.

First, in steps S11 and S12, the target detection section 11 detects atarget so that the leading vehicle detection section 12 detects aleading vehicle based on the target. Next, in step S13, the leadingvehicle detection section 12 determines whether or not a leading vehicleis detected. If Yes in step 13, the present process proceeds to stepS14. In S14, if an obstacle is present at the left side or the rightside of the leading vehicle in the own lane, the crossing overdetermination section 13 determines whether or not the leading vehiclehas passed over a lane marking present at the opposite side of theobstacle. In this case, the crossing over determination section 13 maydetermine that the leading vehicle has passed over the lane markingpresent at the opposite side of the obstacle when the leading vehiclehas actually passed over the lane marking present at the opposite sideof the obstacle.

If Yes in step S14, the present process proceeds to steps S15 and S16,in which the leading vehicle detection section 12 detects the lateraldistance H1 and the width of the leading vehicle. Next, in step S17, theallowance determination section 14 determines whether or not the ownvehicle is allowed to cross over the lane marking based on the lateraldistance H1 and the width of the leading vehicle.

If YES in step S17, the present process proceeds to step S18. In stepS18, even if the own vehicle has crossed over the lane marking when theown vehicle runs in the travel area, the alarm inhibition section 15determines that an alarm is not caused to be issued. Then, the presentprocess is ended.

According to the present embodiment described above, the followingexcellent advantageous effects can be obtained.

In the above configuration, when an obstacle is detected at the right orthe left of the leading vehicle, and the leading vehicle has crossedover the lane marking present at the opposite side of the obstacle,issuing an alarm performed when the own vehicle has passed over the lanemarking is inhibited. In this case, it is determined whether or not analarm indicating that the own vehicle has crossed over the lane markingis necessary, and even if the own vehicle has crossed over the lanemarking, an alarm is not issued if unnecessary. Hence, an unnecessaryalarm can be inhibited from being issued. As a result, an alarmindicating that the own vehicle has crossed over the lane marking can beappropriately issued.

In the above configuration, it is determined whether or not the ownvehicle is allowed to cross over the lane marking based on the size ofthe travel area. If it is determined to be allowed, an alarm isinhibited from being issued. In this case, since it is determinedwhether or not the own vehicle is allowed to cross over the lanemarking, and an unnecessary alarm is inhibited from being issued, anunnecessary alarm can be appropriately inhibited from being issued.

In the above configuration, if the width of the leading vehicle islarger than the lateral distance H1 between the lane marking and thetarget, it is determined that the own vehicle is allowed to cross overthe lane marking. In this case, if the width of the leading vehicle islarger than the lateral distance H1, it is determined that the ownvehicle crosses over the lane marking when running in the travel area,whereby the own vehicle is allowed to cross over the lane marking.Hence, before the own vehicle runs in the travel area, it can bedetermined whether or not the own vehicle is allowed to cross over thelane marking.

Second Embodiment

Next, the second embodiment will be described. In the followingdescription, the configurations similar to those of the above embodimentare denoted by the same reference numerals, and redundant descriptionsare appropriately omitted.

A travel path extending from the center position in the width directionof the leading vehicle may be generated. Based on a lateral distance,which is a distance between a position on the travel path (pathposition) and a lateral position of an obstacle, it may be determinedwhether or not the own vehicle is allowed to cross over a lane marking.In FIG. 5, a travel path T is generated based on, for example, positionsof the leading vehicle obtained at predetermined intervals. Then, theallowance determination section 14 obtains a lateral distance H2 betweenthe position of the leading vehicle M2 on the travel path (pathposition) T of the leading vehicle M2 and the lateral position of theobstacle B, the position being obtained before the leading vehicle M2reaches the travel area R, and the width W of the leading vehicle M2,and determines whether or not the half of the width W of the leadingvehicle M2 is larger than the lateral distance H2. If the half of thewidth W of the leading vehicle M2 is larger than the lateral distanceH2, when the leading vehicle M2 runs in the travel area R, the leadingvehicle M2 crosses over the lane marking D to avoid the obstacle B. Inthis case, when the own vehicle M1 runs in the travel area R followingthe leading vehicle M2, it can be considered that the driver of the ownvehicle M1 purposefully makes the own vehicle M1 cross over the lanemarking D. Hence, when the leading vehicle M2 has crossed over the lanemarking D, if it is determined that the half of the width W of theleading vehicle M2 is larer than the lateral distance H2, it isdetermined that an alarm should not be caused to be issued even if theown vehicle M1 crosses over the lane marking D.

Next, a processing procedure for inhibiting an alarm performed by thedriving support ECU 10 will be described with reference to the flowchartin FIG. 6. The present process is performed instead of the process ofFIG. 4. In FIG. 6, the same steps as those of FIG. 4 are denoted by thesame step numbers. FIG. 6 differs from FIG. 4 in that steps S21 to S23are added.

In steps S11 to S13, the leading vehicle detection section 12 determinesthat a leading vehicle is detected. Next, in step S21, the leadingvehicle detection section 12 obtains a travel path of the leadingvehicle. In step S14, if the crossing over determination section 13determines that the leading vehicle has passed over a lane marking, insteps S22 and S16, the leading vehicle detection section 12 obtains thelateral distance H2 and the width of the leading vehicle. Next, in stepS23, the allowance determination section 14 determines whether or notthe own vehicle is allowed to cross over the lane marking based on thelateral distance H2 and the half of the width W.

According to the present embodiment described above, the followingexcellent advantageous effects can be obtained.

In the above configuration, if the half of the width of the leadingvehicle is larger than the lateral distance H2 between the position onthe path (path position) and the obstacle, it is determined that the ownvehicle is allowed to cross over the lane marking. In this case, it canbe determined whether or not the own vehicle is allowed to cross overthe lane marking based on the positional relationship between theleading vehicle and the obstacle in the lane width direction.

Other Embodiments

The above embodiments may be modified as below.

Even if the width of the leading vehicle is larger than the lateraldistance H1, which is a lateral distance between the lane marking andthe obstacle, when the width of the own vehicle is smaller than thewidth of the leading vehicle, it can be considered that the own vehiclemay run in the travel area without crossing over the lane marking. Inthis regard, in the first embodiment, if the width of the leadingvehicle is larger than the lateral distance H1, the driving support ECU10 determines that the own vehicle is not allowed to cross over the lanemarking. However, this can be modified as below. Even if the width ofthe leading vehicle is larger than the travel area, when the differenceobtained by subtracting the width of the own vehicle from the width ofthe leading vehicle is equal to or more than a threshold value Th2(Th2>0), the driving support ECU 10 may determine that the own vehicleis not allowed to cross over the lane marking. In this case, consideringthe difference between the width of the leading vehicle and the width ofthe own vehicle, it can be accurately determined whether or not the ownvehicle is allowed to cross over the lane marking.

In the first embodiment, it is determined whether or not the own vehicleis allowed to cross over the lane marking based on the width of theleading vehicle. This may be modified so as to determine whether or notthe own vehicle is allowed to cross over the lane marking based on thewidth of the own vehicle. In this case, for example, if the width of theown vehicle is larger than the lateral distance H1 between the lanemarking and the obstacle, it may be determined that the own vehicle isallowed to cross over the lane marking. Hence, regardless of the widthof the leading vehicle, it can be determined whether or not the ownvehicle is allowed to cross over the lane marking. In addition, insteadof using the width of the leading vehicle, a predetermined value may beused. In short, it may be determined whether or not the own vehicle isallowed to cross over the lane marking based on the size of the travelarea.

In the second embodiment, a travel path of the leading vehicle isgenerated to obtain the distance between the travel path and an obstacleas the lateral distance H2 between the position on the path (pathposition) and the obstacle. This may be modified so as to detect arunning position of the own vehicle based on the yaw rate sensor 23, thesteering angle sensor 24, and the vehicle sensor 25 and generate atravel path of the own vehicle to obtain the distance between the travelpath and the obstacle as the lateral distance H2.

When an obstacle is moving, the size of the travel area differs betweenwhen the leading vehicle passes through the travel area and when the ownvehicle passes through the travel area. In this regard, it may bedetermined whether or not the own vehicle is allowed to cross over thelane marking based on the moving speed and the moving direction of theobstacle. Thereby, even when the size of the travel area changes as theobstacle moves, it can be determined whether or not the own vehicle isallowed to cross over the lane marking considering the moving speed andthe moving direction of the obstacle.

In the above configuration, the present invention is applied to avehicle driven by driving operation of the driver. However, the presentinvention may be applied to a vehicle performing follow-up control underwhich the vehicle follows a leading vehicle based on the runningposition of the leading vehicle. Under this follow-up control, when theleading vehicle has crossed over the lane marking to avoid an obstacle,the own vehicle following the leading vehicle also crosses over the lanemarking if the own vehicle is allowed to cross over the lane marking. Atthis time, the alarm inhibition section 15 inhibits an alarm of the ownvehicle.

Although the alarm inhibition section 15 determines that an alarm is notcaused to be issued even when the own vehicle has crossed over the lanemarking. This can be changed so as to change the manner of the alarm toinhibit the alarm from being issued.

As an aspect of the embodiment, a driving support apparatus for avehicle is provided. The apparatus causes an alarm unit (31) to issue analarm based on a lane marking of an own lane in which an own vehicle(M1) runs. The apparatus includes: a leading vehicle detection section(12) that determines a leading vehicle (M2) running in the own lane; acrossing over determination section (13) that determines whether or notthe leading vehicle has crossed over the lane marking present at anopposite side of the target, when a target is present at a left side ora right side of the leading vehicle in the own lane; and an alarminhibition section (15) that inhibits the alarm based on a result of thedetermination whether or not the leading vehicle has crossed over thelane marking present at the opposite side of the target.

If a target such as a stopped vehicle or a structure is present in thelane, a travel area of the own vehicle may narrow. In this case, whenthe own vehicle passes through the travel area, the own vehicle maycross over the lane marking. When the own vehicle crosses over the lanemarking, an unnecessary alarm may be issued.

In this regard, when a target is detected at the right or the left ofthe leading vehicle, and the leading vehicle has crossed over the lanemarking present at the opposite side of the target, issuing an alarmperformed when the own vehicle has passed over the lane marking isinhibited. In this case, it is determined whether or not an alarmindicating that the own vehicle has crossed over the lane marking isnecessary, and even if the own vehicle has crossed over the lanemarking, an alarm is not issued if unnecessary. Hence, an unnecessaryalarm can be inhibited from being issued. As a result, an alarmindicating that the own vehicle has crossed over the lane marking can beappropriately issued.

It will be appreciated that the present invention is not limited to theconfigurations described above, but any and all modifications,variations or equivalents, which may occur to those who are skilled inthe art, should be considered to fall within the scope of the presentinvention.

What is claimed is:
 1. A driving support apparatus for a vehicle, theapparatus causing an alarm unit to issue an alarm based on a lanemarking of an own lane in which an own vehicle runs and comprising: aleading vehicle detection section that determines a leading vehiclerunning in the own lane; a crossing over determination section thatdetermines whether or not the leading vehicle has crossed over the lanemarking present at an opposite side of the target, when a target ispresent at a left side or a right side of the leading vehicle in the ownlane; and an alarm inhibition section that inhibits the alarm based on aresult of the determination whether or not the leading vehicle hascrossed over the lane marking present at the opposite side of thetarget.
 2. The driving support apparatus according to claim 1, furthercomprising an allowance determination section that determines whether ornot the own vehicle is allowed to cross over the lane marking, based ona size of a travel area of the own vehicle, the travel area being otherthan an area of the own lane which is occupied by the target, whereinthe alarm inhibition section inhibits the alarm when the allowancedetermination section determines that the own vehicle is allowed tocross over the lane marking.
 3. The driving support apparatus accordingto claim 2, further comprising a lateral distance obtainment sectionthat obtains a lateral distance between the lane marking and the targetas a size of the travel area, when the target is present at a left sideor a right side of the leading vehicle in the own lane, wherein theallowance determination section determines that the own vehicle isallowed to cross over the lane marking, when a width of the leadingvehicle is larger than the lateral distance.
 4. The driving supportapparatus according to claim 3, further comprising: a calculationsection that calculates a difference obtained by subtracting a width ofthe own vehicle from the width of the leading vehicle; and a thresholdvalue determination section that determines whether or not thedifference is equal to or more than a predetermined threshold value,wherein the allowance determination section determines that the ownvehicle is not allowed to cross over the lane marking, when thedifference is equal to or more than the threshold value.
 5. The drivingsupport apparatus according to claim 2, further comprising a lateraldistance obtainment section that obtains a lateral distance between thelane marking and the target as a size of the travel area, when thetarget is present at a left side or a right side of the leading vehiclein the own lane, wherein the allowance determination section determinesthat the own vehicle is allowed to cross over the lane marking, when awidth of the own vehicle is larger than the lateral distance.
 6. Thedriving support apparatus according to claim 1, further comprising: apath generation section that generates a travel path of the leadingvehicle; a lateral distance obtainment section that obtains a secondlateral distance between the target and a position of the leadingvehicle on the travel path, the position being obtained before theleading vehicle reaches a lateral position of the target, when thetarget is present at a left side or a right side of the leading vehiclein the own lane; and an allowance determination section that determinesthat the own vehicle is allowed to cross over the lane marking, whenhalf of a width of the leading vehicle is larger than the second lateraldistance, wherein the alarm inhibition section inhibits the alarm whenthe allowance determination section determines that the own vehicle isallowed to cross over the lane marking.
 7. The driving support apparatusaccording to claim 2, further comprising a moving state detectionsection that detects a moving speed and a moving direction of the targetin the own lane, wherein the allowance determination section determineswhether or not the own vehicle is allowed to cross over the lane markingbased on the moving speed and the moving direction.